RESUMO
BACKGROUND: The frequency of HLA-DQ2 and DQ8 predisposing genotypes for celiac disease (CD) has shown significant variation among different world regions and has not been previously determined among the highly interbred Brazilian population. The aim of this study was to investigate the frequency of these genotypes among Brazilian newborns (NB). METHODS: We typed DQA1*05 - DQB1*02 (DQ2.5) and DQA1*03 - DQB1*03:02 (DQ8) alleles in 329 NB using qPCR technique. Subsequently we confirmed our results by PCR-SSP using a reference kit which further identified DQ2.2 (DQA1*02:01 - DQB1*02). RESULTS: Among the 329 NB, using qPCR technique: 5 (1.52%) carried both DQ2.5 and DQ8 variants; 58 (17.63%) carried only DQ2.5 (DQA1*05 and DQB1*02) and 47 (14.29%) carried only the DQ8 (DQA1*03 and DQB1*03:02) variant. The use of the PCR-SSP method yielded further information; among the 329 samples: 34 (10.34%) tested positive for DQ2.2 and among the 47 previously DQ8 positives samples, we found 10 (3.04%) that also tested positives for DQ2.2. CONCLUSION: 43.7% of the analyzed individual tested positive for at least one of the CD predisposing HLA-DQ genotypes in our group of Brazilian NB. The highest frequency was found for DQ2.5 positive subjects (17.6%) followed by DQ8 (11.3%); DQ2.2 (10.3%); DQ8 and DQ2.2 (3.0%); DQ2.5 and DQ8 (1.5%). We found no positive sample for DQ2.5 associated with DQ2.2.
Assuntos
Alelos , Doença Celíaca/genética , Frequência do Gene , Predisposição Genética para Doença , Antígenos HLA-DQ/genética , Brasil/epidemiologia , Doença Celíaca/epidemiologia , Feminino , Humanos , Recém-Nascido , Masculino , Reação em Cadeia da Polimerase em Tempo RealRESUMO
BACKGROUND: Although it is known that first degree relatives of celiac patients have an increased risk for celiac disease few studies are available on its incidence. We investigated the incidence of serologic conversion and of new cases of celiac disease among first degree relatives with negative results at a first screening. METHODS: From a total of 634 first degree relatives of 186 biopsy-proven celiac disease patients diagnosed between October 2000 and October 2010, 450 subjects agreed to participate in the study (Group I), and underwent serologic screening. Between January 2010 and October 2012, out of the initial group of 450, 205 previously sero-negative subjects consented to participate in a second stage of the study and undergo new serologic testing (Group II). All serologically positive individuals of both groups (I and II) were genotyped for celiac disease-predisposing alleles (HLA-DQ2/DQ8). RESULTS: 19 subjects (4.2%) out of the 450 subjects of Group I disclosed positive serologic results, presence of DQ2 and/or DQ8 alleles and celiac disease-compatible mucosal abnormalities. The 205 previously negative first degree relatives from Group II that underwent new serologic testing disclosed eight sero-converted subjects. Mucosal abnormalities in five of these patients confirmed the diagnosis of celiac disease. During the 10-year period of the study the incidence of sero-conversion was 8/205 and the incidence of biopsy-proven celiac disease cases was 5/205. CONCLUSIONS: Our data are coincident with other works on this subject and confirm once again that relatives of celiac patients, especially first degree relatives are at high risk of developing celiac disease. In view of the relatively low incidence further studies are needed to try to establish a useful and cost-effective algorithm for follow-up of relatives of celiac patients.
Assuntos
Doença Celíaca/diagnóstico , Doença Celíaca/epidemiologia , Família , Imunoglobulina A/sangue , Transglutaminases/imunologia , Adolescente , Adulto , Alelos , Biópsia , Brasil/epidemiologia , Doença Celíaca/genética , Criança , Pré-Escolar , Feminino , Seguimentos , Proteínas de Ligação ao GTP , Predisposição Genética para Doença , Testes Genéticos , Genótipo , Antígenos HLA-DQ/genética , Humanos , Incidência , Intestino Delgado/patologia , Masculino , Pessoa de Meia-Idade , Prevalência , Proteína 2 Glutamina gama-Glutamiltransferase , Adulto JovemRESUMO
Brachiaria (Trin.) Griseb belongs to the family Poaceae, and within the genus, apomixis or sexuality is present in different accessions of the same species. The majority of Brachiaria species are polyploid and apomictic, making strategies for crop improvement by breeding very intricate. In spite of the high frequency of apomictic polyploids, the relationship of polyploidy and hybridization with apomixis in Brachiaria is still unclear. Further analysis requires detailed knowledge regarding the genomic composition of the polyploids. The present work introduces the use of fluorescent in situ hybridization (FISH) into cytogenetic analysis of Brachiaria. Physical mapping of heterologous rDNA sequences, associated with conventional karyotyping of the B. brizantha diploid sexual (BRA 002747) and the tetraploid apomictic (BRA000591) accessions, provided evidence of the latter being of allopolyploid origin. Based on our results and on previous knowledge on apomixis in B. brizantha, we suggest that the origin of apomixis was probably a consequence of hybridization.